Known from the publication DE 103 05 241 A1 is a 6-speed or 7-speed dual clutch transmission. The dual clutch transmission comprises two clutches, each connected with their inputs to the drive shaft and with their output to one of the two transmission input shafts. The two transmission input shafts are coaxially positioned each other. In addition, two countershafts are arranged to be axially parallel to the transmission input shafts, their idle gears mesh with the fixed gear wheels of the transmission input shafts. Furthermore, coupling devices that are axially movable and arranged on the countershaft in a rotationally fixed manner to shift the respective gear wheels. Each selected ratio is transferred by the drive gear wheels to a differential transmission. To achieve the desired gear ratio steps in this known double clutch transmission, a vast number of gear planes are required, so that a significant amount of installation space is needed.
In addition, a spur gear change speed transmission is known through the publication DE 38 22 330 A1. The spur gear change speed transmission comprises a double clutch, that is shiftable under power, where one part is connected with a drive shaft and the other part with a hollow drive shaft, rotatably supported on the drive shaft. For certain gear ratios, the drive shaft can be coupled with the hollow drive shaft via a shifting device.
Known from the publication DE 10 2004 001 961 A1 is a power transmission with two clutches, each of which are assigned to a partial transmission. The transmission input shafts of the two partial transmissions are positioned coaxial to each other and mesh, via fixed gear wheels, with idle gears of the designated countershaft. The respective idle gears of the countershafts can be connected, in a rotationally fixed manner, with the respective countershaft via designated shifting devices. The particular idle wheels of the countershaft can be connected via the assigned shifting devices with the associated countershaft in a rotationally fixed manner. A double clutch transmission is known from this publication, which absolutely requires at least six gear planes. Hence, the needed spatial installation requirement, in axial direction, increases with such transmission, so that the installation options are significantly limited with such known transmission.